Browsing by Subject "saponins"

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  • Kamyab, Elham; Goebeler, Norman; Kellermann, Matthias Y.; Rohde, Sven; Reverter, Miriam; Striebel, Maren; Schupp, Peter J. (2020)
    Sea cucumbers are bottom dwelling invertebrates, which are mostly found on subtropical and tropical sea grass beds, sandy reef flats, or reef slopes. Although constantly exposed to fouling communities in these habitats, many species are surprisingly free of invertebrate epibionts and microfouling algae such as diatoms. In our study, we investigated the anti-fouling (AF) activities of different crude extracts of tropical Indo-Pacific sea cucumber species against the fouling diatom Cylindrotheca closterium. Nine sea cucumber species from three genera (i.e., Holothuria, Bohadschia, Actinopyga) were selected and extracted to assess their AF activities. To verify whether the sea cucumber characteristic triterpene glycosides were responsible for the observed potent AF activities, we tested purified fractions enriched in saponins isolated from Bohadschia argus, representing one of the most active anti-fouling extracts. Saponins were quantified by vanillin-sulfuric acid colorimetric assays and identified by LC-MS and LC-MS/MS analyses. We were able to demonstrate that AF activities in sea cucumber extracts were species-specific, and growth inhibition as well as attachment of the diatom to surfaces is dependent on the saponin concentration (i.e., Actinopyga contained the highest quantities), as well as on the molecular composition and structure of the present saponins (i.e., Bivittoside D derivative was the most bioactive compound). In conclusion, the here performed AF assay represents a promising and fast method for selecting the most promising bioactive organism as well as for identifying novel compounds with potent AF activities for the discovery of potentially novel pharmacologically active natural products.
  • Rauma, Asta (Helsingin yliopisto, 2018)
    The literature review focused on quinoa saponins, on their extraction, isolation and chromatographic analysis. The aim of this study was to develop a quantitative and qualitative analysis method for saponins in quinoa. Gas chromatograph (GC) was used for separation. Saponin aglycones were indentified by mass spectrometry (MS) and quantified by flame ionization detector (FID). Sample pretreatment included extraction of fat soluble compounds and saponins by accelerated solvent extraction (Dionex ASE). Saponin aglycones liberated by acid hydrolysis followed by liquid-liquid extraction. Aglycones were derivatised to silylethers and analysed with GC-MS/FID. Finally this method was used to analyse saponins in washed and pearled quinoa seeds. Method evaluation included repeatability test (4 separate days, total n = 14). Average, standard deviation, relative standard deviation and Horrat(r) - value were calculated for the results. Method realability was evaluated by recovery test. Known amount of saponin was added to flour samples (n = 3). Additions responded 6, 4 µg, 12, 8 µg and 32 µg hederagenin aglycone. Four saponin aglycones, oleanolic acid (ole), hederagenin (hed), serjanic acid (ser) and phytolaccagenic acid (phy), were successfully identified in all samples by method prescribed. Method was repeatabale for ole and ser quantition but not for hed and phy. Satisfactory recovery, 80 %, was achieved on 32 µg addition level. Recoveries for 6, 4 µg and 12, 3 µg addition levels were 76 and 66 %. Results could be explained by aglycones pH dependent solubility combined to inaccurate pH adjustment after hydrolysis. In the future neutralization step should be revaluated. Washing reduced saponins 20–58 % and pearling reduced 58 % saponins in quinoa seeds. However pearling caused loss of protein from 12, 3 % to 5, 8 %.
  • Fedotov, Anna (Helsingin yliopisto, 2021)
    The popularity of oats (Avena sativa L.) as a food grain and their use in plant-based foods has increased in recent years due to, among other things, the proven positive health effects of oat components. Oat saponins are bioactive compounds that can potentially affect health (both positively and negatively), as well as technological properties and taste of oats and oat products. The main saponins of oat grain are avenacosides A and B. The aim of this study was to investigate the variation of avenacoside concentrations in oats grown in Finland. The samples were 20 batches of laboratory-scale dehulled, unheated oat grains (groats, G samples). In addition, the effect of processing on avenacoside concentrations was investigated for the same 20 grain batches. Oat processing included a milling process, including heat treatment, flaking, and grinding (NFL samples), and bread making (LP samples). In addition, the effect of storage (6 months at room temperature) of NFL samples on avenacosides concentrations was studied. Avenacosides were extracted from the samples with methanol-water solvent overnight at room temperature and determined by high performance liquid chromatography. The results of the study showed that the mean avenacoside concentrations in the G samples ranged from 371 to 721 µg/g dry matter. Concentrations among G samples were statistically significantly different (p<0.05). The differences may be due to genetic factors and oat growth conditions. As a result of processing, avenacoside concentrations decreased in the following order: G> NFL> LP. The milling process reduced avenacoside concentrations by an average of 26% (G vs. NFL). Bread saponin concentrations were on average 49% lower than those in oat flake flour (LP vs. NFL). Overall, concentrations decreased by an average of 62% (G vs. LP). Presumably, saponin concentrations could have been affected e.g. by heating and β-glucosidase enzyme (endogenous in NFL and produced by yeast in LP). The storage experiment showed that avenacosides were stable in NFLs during six months of storage. Data obtained can be used in other oat saponin studies and in the development of oat products. The study provided important information about the effects of oat processing on avenacoside concentrations and can be continued by analysing avenacosides levels under different baking conditions and taking samples at different production stages. The effect of storage on avenacosides under different conditions could be also studied.